Multi-sensor biometric information monitoring device

Abstract

An apparatus for monitoring biometric information blood of a user that contains a housing that includes an electropermanent magnet, a battery, a processor, and a radio transmitter. A cap is magnetically coupled to the housing when a current is passed through a coil of the electropermanent magnet thereby compressing a portion of tissue of the user between the housing and the cap. By varying the compressive force applied to the tissue, the apparatus monitors at least one of blood pressure and heart rate from the response.

What is claimed is: 
     
       1. An apparatus for monitoring biometric information of a user comprising:
 a housing that includes an electropermanent magnet, a battery, a processor, and a radio transmitter; 
 a cap that is magnetically coupled to the housing by the electropermanent magnet when a current, controlled by the processor, is passed through a coil of the electropermanent magnet thereby compressing a portion of tissue of the user between the housing and the cap; and 
 a magnetic field sensor, 
 wherein a compressive force applied to the tissue is operably controlled by the processor which varies a magnetic field strength applied to the cap, 
 wherein the magnetic field sensor measures a response of the tissue while the magnetic field strength is varied to produce a signal waveform, and 
 wherein blood pressure is determined by the processor while varying a pulse width applied to the electropermanent magnet which in turn varies a compressive stress across tissue. 
 
     
     
       2. The apparatus of  claim 1 , wherein the pulse width is varied between 10-100 microseconds. 
     
     
       3. The apparatus of  claim 1 , wherein the processor determines heart rate by detecting occurrences of local maxima in the signal waveform associated with local minima of a first differential of the signal waveform. 
     
     
       4. The apparatus of  claim 1 , further comprising a multi-sensor that includes at least one of a temperature sensor, an oxygen saturation sensor and a motion sensor, wherein the multi-sensor monitors at least one of oxygen saturation, temperature, body motion from the response of the tissue. 
     
     
       5. The apparatus of  claim 4 , wherein the multi-sensor comprises a thermistor, and wherein the thermistor is embedded into the housing to detect a temperature of a user's scalp. 
     
     
       6. The apparatus of  claim 4 , wherein the multi-sensor further comprises a dual wavelength transmitter and a photodiode receiver to measure arterial oxygen saturation using either transmitted or reflected light. 
     
     
       7. The apparatus of  claim 4 , wherein the multi-sensor comprises an accelerometer that is calibrated against activity of the user. 
     
     
       8. The apparatus of  claim 1 , wherein the processor varies the current supplied to the electropermanent magnet to periodically release the portion of the tissue of the user. 
     
     
       9. The apparatus of  claim 1 , wherein varying the magnetic field strength over time and measuring the response of the tissue measures elastic properties of blood vessels within a user's body. 
     
     
       10. The apparatus of  claim 1 , wherein the processor executes instructions in accordance with a physiological context that account for interrelationships of processes in a user's body.